The present invention refers to a process for the preparation of fructose and fructose-rich syrups suitable for human consumption, from whole raw xerophyte plants and, more particularly, it is related to a process for the obtention of fructose and fructose-rich syrups for human consumption from raw xerophyte plants without having resource to the traditional cooking process, whereby to render the bagasse obtained suitable for the obtention of alpha-cellulose.
In the conventional process used through many years to manufacture distilled liquors of the type of tequila from the fermented juices of xerophyte plants, particularly of the genus Agave, such as Agave tequilana, it was mandatory to subject only the core portions of the Agave plant to an intensive cooking step at high temperatures and pressures in order to brake down the cellulosic walls of the plant material for the purpose of facilitating the removal of the juices contained therein by means of suitable expelling process. This cooking step, however, generated substantial amounts of partially carbonized matter which was entrained in a colloidal state in the liquors thus considerably affecting the quality of the liquor expressed. Also, said cooking step produced serious scorching, discoloration, impurification and hardening of the fibrous material, whereby said material had to be considered as practically useless for the obtention of good quality fibers and cellulose.
Despite the very important drawbacks introduced in the process of treating xerophyte plants by the cooking stage which had been considered indispensable heretofore, manufacturers of alcoholic beverages of the above mentioned type had not been able to avoid the use of said cooking step, inasmuch as otherwise it was not possible to achieve a complete extraction of the juices contained in the plant material for further treatment by fermentation and distillation to obtain said liquors.
The colloidal impurities introduced in the expelled juices by virtue of the cooking step, prevented the obtention of juices suitable for being concentrated to form highly concentrated juices or syrups that could be thereafter spray dried to obtain fermentable powders, whereby the possibilities of locating the plants for manufacturing distilled liquors were restricted by economical considerations only to those zones which were in the neigborhood of the regions in which said xerophyte plants were grown, as transportation of the whole plants to remote locations was absolutely uneconomical.
On the other hand, the transportation of liquid juices could not be effected for economical reasons and storage of concentrated syrups obtained therefrom was materially impossible because said syrups were highly unstable, whereby they suffered autogenous fermentation in relatively short periods of time, which prevented its massive transportation at long distances.
In U.S. Pat. No. 3,928,121, patented Dec. 23, 1975 to the same applicant, a process for the obtention of fermentable powdered syrups and alpha-cellulose from xerophyte plants is disclosed, that fully overcomes the above mentioned problems, by avoiding the cooking step and replacing the same with a novel extraction stage which was effected by means of an aqueous liquor at a temperature of from 85 to 92.degree. C, with which the extraction of the juices from the plant material was effected in a highly efficient manner, thus avoiding the contamination of the juices with colloidal matter generated by the said cooking step. This method therefore permitted the production of highly concentrated syrups capable of being spray dried to obtain fermentable powders and also permitted the production of highly pure alpha-cellulose, inasmuch as the scorching and hardening of the bagasse, caused by the cooking step, were no longer existant in the process.
The concentrated syrups obtained by means of the process of U.S. Pat. No. 3,928,121, while containing important concentrations of fructose, however, resisted any attempt to crystallize the same for the recovery of said important food product, for reasons that are not clearly understood up to the present date. Therefore, the syrups obtained by the said process were only suitable for being either directly fermented to be converted into distilled liquors or for being spray dried to form fermentable powders which only use was to also obtain alcoholic liquors upon rehydration thereof, fermentation and distillation. In other words, the syrups obtained by the process of U.S. Pat. No. 3,928,121 could not be subjected to crystallization to obtain crystallized fructose and were not in themselves apt for direct human consumption in substitution of the very well known sweetening syrups obtained from grains such as corn and the like.
Therefore, while the process of U.S. Pat. No. 3,928,121 represents a breakthrough in itself, because a very important advance in the art of processing xerophyte plants was provided thereby, any attempt to obtain pure fructose by crystallization and any attempt to render the concentrated syrup of said process suitable for direct human consumption for sweetening purposes, were rather fruitless in view of the fact that, for reasons not understood, said syrups could only be spray dried but not crystallized to recover the pure sugar.